When storing radioactive elements in a transitional or intermediate store, extreme care must be taken to prevent damage being caused by radiation to the environment. Such a store must be capable of withstanding exceptional loads from external events such as earthquakes, explosions, and aircraft crashes. Moreover, radioactive elements produce considerable amounts of heat, which heat must also be dissipated safely.
When used fuel elements from nuclear reactors are to be reconditioned, it is known to store them in thick-walled containers made of spherodial graphite cast iron. These containers are designed to withstand external influences and are set up in a building adapted for such storage, i.e., a building so ventilated that the heat which is produced by the fuel elements and is given off by the cast iron containers to the air can be discharged through the building roof in natural circulation. Transitional stores for elements with vitrified highly radioactive waste are also known wherein a plurality of elements are enclosed in a container made of cast steel. The walls of these containers generally include cooling water pipes connected to a heat exchanger which in normal operation conducts the heat to a utilization stage. The container is situated in a reinforced concrete building dimensioned to withstand external influences or actions, which building also includes an air cooling system with natural circulation to ensure adequate dissipation of heat to outside the containers in the event of failures in the water cooling system.
The heretofore known containers made of cast iron or cast steel do in fact discharge, in a relatively problem free manner, the heat which is produced by radioactive elements, and likewise allow utilization of the discharged heat at temperature levels above 100.degree. C. The manufacture of these containers however is very expensive, as are the materials from which they are made.